ATLANTA -- An estimated 100,000 people from all over the U.S. jammed downtown Atlanta and marched with Rev. Jesse Jackson to celebrate the 40th anniversary of the Voting Rights Act -- and to urge Congress to renew the historic piece of legislation.

The march began about an hour late at the Russell Federal Building, partly because of the large number of dignitaries taking part in the event. Politicians from Atlanta mayor Shirley Franklin to U.S. Reps. Charles Rangel (D-NY) and Nancy Pelosi (D-CA) joined entertainers Harry Belafonte and Stevie Wonder and thousands of chanting and singing demonstrators for the "Keep The Vote Alive" event that streamed down Martin Luther King Jr. Drive and wound up at Morris Brown College's Herndon Stadium for a rally.

Organizers hope the Congress and President Bush will extend key provisions of the landmark law, which was signed in 1965 by President Lyndon Johnson. The law expires in 2007.

"Forty years later, we're still marching for the right to vote," said U.S. Rep. John Lewis (D-GA), who participated in the civil rights struggles that helped secure passage of the law.

"Don't give up, don't give in. Keep the faith, keep your eyes on the prize."

Activists from across the country flocked to the rally to join Lewis, NAACP President Bruce Gordon and Jackson, who heads the Rainbow/PUSH Coalition.

At the raucous rally at Herndon Stadium, Jackson took the stage and energized supporters with his trademark quotes of "I am somebody" and "Keep hope alive."

"The right to vote does not endanger, but we must protect it against discrimination," Jackson said.

Civil rights groups fear conservatives will try to modify two key provisions of the law. One requires nine states, mostly in the South, to get federal approval before changing voting rules. The other requires election officials to provide voting material in the native language to immigrant voters who don't speak English.

Activists also used the rally to protest Georgia's recently passed voter identification law, which critics call the most restrictive in the country.

If the bill is approved by the Department of Justice, Jackson warned on Friday, it could "spread like a virus" to other states. Rainbow/PUSH is among a list of objectors that have contacted the Department of Justice asking the agency not to approve the law.